Pump unit



May 7, 1935.

Patented May 7, 1935 PUMP UNIT Charles L. Babb, Milwaukee, Wis.,assignorI to Allis-Chalmers Manufacturing Company, Milwaukee, Wis., acorporation of Delaware Application June 14, 1933, Serial N0. 675,666

Claims.

This invention relates to improvements in fluid pumping units and moreparticularly to units in which the fluid to be displaced isutilized tocool the operating means of the pump.

In pumping units driven by electric motors, it is advantageous to coolthe motor by the fluid to be displaced to thereby obtain intense coolingof the motor which permits increase in the rating thereof. The motorthen can be totally enclosed and is thereby suited for outdoor operationwithout a protective cover or housing. It is necessary that a unit ofsuch character be entirely self -contained and such unit is thereforepreferably provided with a complete built-in lubricating system.

Thebearings of the unit should be accessible and such bearings as wellas the rotor of the motor y should be removable from the unit withoutnecessitating dismounting of the cooling jacket of the motor and withthe minimum of disturbance to other portions oi the unit. The bearingsof the unit should also preferably be so located as to be protected frominjury due to forces external to the unit during transportation thereof.The pump is preferably of a type in which the end thrust is compensatedto reduce the duty of the thrust bearing and thereby to reduce thepossibilities of failure of the unit during operation thereof.

It is therefore among the objects of the present invention to provide anelectric motor driven iluid pumping unit in which the motor is totallyenclosed and is cooled only by the fluid to be displaced.

Another object of the invention is to provide a motor driven pumpingunit in which all of the bearings are protected from injury by forcesexternal to the unit.A I

Another object of the invention is to provide a motor driven pumpingunit in which only the minor operating portions of the structure areexposed and are accessible without disassembly of the unit.

Another object of the present invention is to provide a motor drivenfluid pumping unit in which all of the bearings of the motor and of thepump are accessible without disturbance of the fluid conveying portionsof the unit.

Another object of the present invention is to provide an electric motordriven fluid pumping unit in which the motor amature andthe bearings forthe amature may be removed without dismounting the cooling Jacket of themotor.

Another object of the present invention is to provide a motor drivenpumping unit having a lubricating pump driven by the motor for sup- (Cl.ID3-87) plying lubricant under pressure to the bearings of the unit froma lubricant reservoir.

Another object of the present invention is to provide a motor drivenpumping unit in which the lubricant for the bearings of the motor and ofthe pump is cooled by the fluid to be displaced.

Another object of the present invention is to provide a motor drivenrotary pumping unit in which the fluid leaking past the sealing means ofthe pump is collected and returned to the fluid line.

y Objects and advantages, other than those above set forth, will beapparent from the following description when read in connection with theaccompanyingdrawing which illustrates one embodiment of the presentinvention partially in longitudinal cross-section.

Referring more particularly to the drawing by characters of reference,reference numeral I generally designates an electric motor of any typeknown in the art, the type being generally determined by the nature ofthe source of current available for the supply of such motor. rMotor Idrives a rotary pump generally designatedby 2 and which is preferably ofthe centrifugal type. Motor I and pump 2 are connected by hollowcylindrical member 3 preferably of the same diameter as the diameter ofthe motor and pump -casings which member maintains' the motor and thepump in proper alinement. `The motor and pump as a unit may thus berested directly on a foundation without the interposition of thebed-plate usually necessary for maintaining the pump and the motor inthe proper alinement. Motor I is provided with a housing 4 ofsubstantially cylindrical shape and preferably made of forged steel andcontains the stator 6 of the motor. The rotor or armature l of the motoris rotatably supported in bearings 8 and 9 mounted in covers II and I2secured to housing 4 in air tight relation therewith. As will appearhereinafter, the cooling of the motor is effected through the outersurface of housing 4. thereby providing for direct cooling of stator 6as a result of the contact of stator 6 with housing 4 which issubstantially surrounded by the fluid being pumped. A fan I3 mounted onthe shaft of the motor is provided to circulate air around rotor I andover the inner surface of housing 4 to provide for the transmission ofheat libr erated in rotor 'I to the fluid flowing over housing 4. Theouter surface of housing 4 is provided with longitudinal cooling fins I4and is surrounded by a jacket I6 secured to housing 4 in fluid tightrelation therewith.

The fluid to be propelled is drawn through a suction pipe il having aninlet opening le preierably coaxial with the motor. Pipe il is dividedinto a plurality oi` branches connected with jaclret i@ through lateralopening such as is and 2l, a portion of the branches, at least, beingpreferably welded to a jacket lb. Such construction avoids the use ofthe large removable seal which would be necessary ii pipe ll wereactually connected with the space defined by housing 4 and jmlret i6.The several branches of pipe il also constitute a guard protectingbearing 8 from possible imuries from external forces and objects duringtransportation and operation ci the unit. Each branch or" pipe il ispreferably constituted oi a plurality of portions so bent and providedwith suitable flanges as to permit removal of a portion of pipe il whenit is desired to remove bearing 3, cover il and rotor l' of motor forinspection or repairs. Such removal may then be effected withoutdisturbing jacket if; or the portions of the inlet pipe connectedtherewith.

Jacket lli is directly connected by cylindrical member 3 with the casing3 oi centrifugal pump Casing 23 supports journal bearings 24 and and athrust bearing 2l' for the impeller shaft of the pump. in the presentembodiment, bearing 2G and thrust bearing 2l are assembled in a commonhousing. Motor shaft 28 is connected with the shaft or motor l by meansof a nexible coupling 2li which permits smooth running of the unitirrespective of any rnisalinernent of rotor Al and of shaft resultingfrom inaccuracies in the different bearing. Casing 23 is provided withan inlet passage Si connected with jacket i6 through a heat exchanger32, the purpose of which will appear hereinafter. From inlet passage Si,the fluid progresses in an axial direction through one or more pumpingstages, each stage comprising an inlet passage 33 leading to an impellerfixedly mounted on shaft 28 from which the duid issues into a dischargepassage 3G connected with the inlet passage of the next stage by apassage 3l. After passing through the first group oi stages, the iiuidis conducted by way of a passage 38 to the inlet passage of the firststage oi a second group of stages wherein the fluid progresses axiallyin a direction opposite to the direction of progression in the iirstgroup oi stages. `Where the above method of stage arrangement is used,the thrust exerted on the shaft by the reaction oi the huid issubstantially balanced and the duty of the thrust bearing is therebysubstantially reduced. The fluid issues from the last stage ci the pumpat substantially mid-length of casing 23 into a discharge passage SQwhich preferably extends parallel to the anis of the pump and is solocated as to be surrounded by the inlet passages of the second group ofstages of the pump. The fluid is discharged from passage 39 into adischarge pipe H having the outlet opening 42 thereof preferably locatedcoaxially with pump 2, motor i and inlet opening il?. Such aconstruction permits installation oi the unit in place of a portion ofthe pipe containing the fluid to be propelled thereby requiring aminimum amount of space for the installation oi the pump. Discharge pipe4l is supported against casing 23 by a brace or braces Pipe di and braceH3 then constitute a guard which protects bearings 28 and 21 frompossible injury during transportation or operation of the unit. Shaft228 is sealed against casing 23 by suitable means such as stuiiing boxesil and 4B .having receptacles 4l and 43 associated thereapodera withwhich collect any uid leaking through the stuffing boxes. The two groupsof Y stages are separated by a chamber lili which collects any iuidtending to leak from the pump casing between the groups of stages undera pressure head which is equal to substantially one-haii oi the pressurehead produced by the entire pump. The fluid accumulating in chambers 4l,43 and 49 is drained from the chambers by suitable means (not shown) andreturned to the iiuid line.

The lubricant for the bearings oi the unit is supplied from a reservoir5i which is preferably mounted Within cylindrical member 3 and fromwhich the lubricant is circulated to the several bearings through asuitable piping system by means of a pump 52 driven by motor l andnerein shown as being mounted at the outboard end of shaft 28. Pump 52circulates the lubricant through a pipe 53 which is a part o1" heat eX-changer 32 in which the heat removed from the bearings by the lubricantis dissipated to the fluid to be propelled. From pipe 53 the lubricantis distributed to the several bearings oi the unit and is returned toreservoir 5i by suitable piping.

It will be appreciated that, as a result of the construction hereindescribed, the pumping unit contains only a small number oi exposedmoving parts which are adequately protected by cylindrical member 3 andthe inlet and outlet pipes. Such moving parts are accessible tlnougb.apertures in suoli member which apertures rnay be entirely closed bysuitable covers to protect such moving parts from the edect ci weather.Lubrication oi the unit is automatically maintained as long as the unitis in operation and needs no attention other than initial provision oian adeouate supply oi lubricant in reservoir 5i. The unit, due toelimination of a base plate, is light in iveight and may .be installedon foundations'of minimum dimensions. All the bearings of the unit areaccessible for inspection and removal thereof Without disassembly of theunit. and the rotor of the motor may be removed with a minimum amount ofdifficulty incident to the weatherproof construction of the motor. Thestator of the motor is intensely cooled by direct contact of such statorwith the cooling iluid through the wall of housing 4 and only the lossesoi rotor l need be transferred to housing 4 by means of air circulatedAbya fan i3 of reduced dimensions. The windage losses are thereforeconsiderably reduced as compared to the Windage losses in e. rotorwherein the heat dissipated in the stator must also be removed by aircirculation. The cooling or the motor is thus obtained at the highestrate possible and the rating of the motor may therefore be increased fora given size of the motor. The cooling oi the lubricant from the severalbearings permits operation ci such bearings with a 'minimum danger offailure thereof during operation oi the unit. The'entire unit may bebuilt, assembled, and tested in the factory before shipment with aminimum expenditure of time and with the minimum of diillculty.

Although but one embodiment of the present invention has beenillustrated and described, it will be apparent to those skilled in theart that various changes and modifications may be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims.

It is claimed and desired to secure by Letters Patent:

l. 1n a iiuid pumping unit, an electric motor having a :duid tighthousing inclosing a stator and a rotor and bearings for said rotorarranged externally of the housing, a jacket coaxially surrounding saidhousing in sealing engagement therewith, a suction pipe discharging intosaid jacket and constituting a guard for one of said bearings, a pumphaving a shaft driven by said motor and having a casing, journal andthrust bearings for said shaft, said bearings being arranged externallyof the casing thereof, means for connecting said casing with said jacketin alinement therewith, means foi conducting fluid from said jacket tothe inlet of said pump, and a discharge pipe for said pump, saiddischarge pipe constituting a guard for one of said journal bearings and.for said thrust bearing.

2. In a fluid pumping unit, an electric motor having 'a uid tighthousing inclosing a stator and a rotor and bearings for said rotor, ajacket coaxially surrounding said housing in sealing engagementtherewith, a suction pipe discharging into said jacket, a pump having ashaft driven by said motor and having a casing and bearings for saidshaft, said bearings being arranged externally of said casing, areservoir for lubricant, a pump driven by said motor and supplyinglubricant to said bearings from said reservoir, means for connectingsaid casing in alinement with said jacket, said reservoir being arrangedwithin said connecting means, means for conducting fluid from saidjacket to the inlet of said pump, and a' discharge pipe for said pump,said discharge pipe forming a guard for said lubricant pump.

3. In a fluid pumping unit, an electric motor having a fluid tighthousing inclosing a stator and a rotor and bearings for said rotor, ajacket coaxially surrounding said housing in sealing engagementtherewithl suction -pipe discharging into said jacket, a pump having ashaft driven byl said motor and having a casing and bearings for saidshaft, said bearings being arranged externally of said casing, means forconnecting said jacket in coaxial alinement with said pump casing, areservoir for lubricant, said reservoir being arranged within saidconnecting means, a pump driven by said motor and supplying lubricant tosaid bearings from said reservoir, a heat exchanger having a passageconnecting said jacket to the inlet of said pump and having /anotherpassagevconnecting said lubricating pump with said bearings, and adischarge pipe for said pump. said suction and said discharge pipesforming guards for exposed portions of the lubricating system. Y

4. In a fluid pumping unit, an electric motor having afluid-tighthousing enclosing the stator and the rotor thereof and bearings for saidrotor arranged externally of the housing, a jacket coaxially surroundingsaid housing in sealing engagement therewith, a suction pipe discharginginto said jacket and constituting a guard for one of said bearings, apump having a shaft driven by said motor and having a casing and havingjournal and thrust bearings for said shaft, all of said bearings beingarranged externally of said pump casing and being removable withoutinterference from and with said 'motor housing and said pump casing,means for connecting said casing with said jacket in alinementtherewith, means for conducting fluid from said jacket to the inlet ofsaid pump, and a discharge pipe for said pump, said discharge pipeconstituting a guard for one of said journal bearings and for saidthrust bearing.

5. In a fluid pumping unit, an electric motor having a housing enclosinga stator and a rotor, said housing having end portions removableseparately from other portions thereof, bearings for said motorsupported only by the end portions of said housing, a jacket coaxiallysurrounding said housing in sealing engagement therewith, a suction pipedischarging into said jacket, a pump having a shaft driven by said motorand comprising a casing and journal and thrust bearings for said shaft,all of said bearings being arranged externally of the casing of saidpump and being removably attached thereto, means for connecting saidcasing with said jackethin alinement therewith, means for conductingfluid from said jacket to the inlet of said pump, and a discharge pipefrom said pump, said suction and said discharge pipes constitutingseparate guards for the bearings arranged at the ends of the unit. i

CHARLES L. BABB.

